A two-wheeled vehicle having a two-wheeled vehicle body, and a front wheel and a rear wheel rotatably provided at the front and rear of the two-wheeled vehicle body, wherein the front wheel is steered by a steering system, can comprise: auxiliary wheels connected to the front wheel at both sides of the two-wheeled vehicle body and steered together with the front wheel around the same rotational center by the steering system steering the front wheel; a lifting device for vertically moving the auxiliary wheels so as to adjust a vertical gap of the auxiliary wheels from the ground; and a gap adjusting device for horizontally moving the auxiliary wheels so as to adjust a horizontal gap of the auxiliary wheels from the two-wheeled vehicle body, wherein the auxiliary wheels are spaced from the ground so as to prevent traveling from being disturbed by the auxiliary wheels during travel, and the auxiliary wheels make contact with the ground so as to restrict the inclination, generated when turning, of the two-wheeled vehicle body, thereby preventing the two-wheeled vehicle body from being inclined at a predetermined angle or more.